We will use recombinant DNA techniques to identify and study regulatory sites in prokaryotic (lambda) and eukaryotic genomes (mouse and human). To further our understanding of the mechanism by which DNA replication is initiated the initiator protein of bacteriophage lambda (product of gene O) will be isolated. Its interaction with the origin of replication will be determined. The precise startpoints of DNA replication will be identified. We will examine the structure of globin genes of mouse and human. Fetal, embryonic and adult genes will be cloned and sequenced. The structures of the gene for heavy chain immunoglobulins isolated from mouse and human DNA will be determined using recombinant DNA techniques. CDNA copies of mRNAs for mouse lambda, gamma and Mu chains cloned into plasmids will be labelled with 32P and used as probe to isolate clones directly from the genomes of mouse and human. Both germ line and differentiated tissue will be studied. These will be sequenced using the Maxam-Gilbert and Sanger techniques. The sequences of the genomic clones will be compared with messenger RNA sequences and any changes accompanying differentiation will be noted. These data should provide an insight into the regulation, and development of the immune system.